Three-dimensional (3-D) objects, such as prototype parts, may be produced directly from computer-aided design databases. Various technologies are known to produce such objects, particularly through the use of layered additive processes. Commercially adapted methods of layered manufacturing use various forms of materials. For example, stereolithography (STL) uses a resin photopolymer resin that is selectively hardened by a laser beam delivering UV light at desirable spots on each thin resin layer. Fused Deposition Method (FDM) uses a plastic filament that is forced through a hot nozzle that deposits the material to form each layer. Laminated Object Manufacturing (LOM) laminates cut sheets of a special paper to create 3D parts. Two processes commonly used are 3D printing and Selective Laser Sintering (SLS). Three-Dimensional printing (3DP) uses adhesive droplets deposited on each thin powder layer to create bonding of powder particles in selected spots of each layer. Selective Laser Sintering (SLS) selectively bonds powdered material using laser. SLS works by depositing and heating by means of a scanning laser beam, which bonds powder material at selected locations of the powder layer. The powder material may include polymer, ceramic, or metal.
However, layer-by-layer selective bonding processes, such as SLS and 3-D Printing, are time consuming and expensive. For example, those methods that use a laser incur the high cost of the laser and the low scanning speed due to relatively wide cross-section area per layer for sintering compared to the beam size. For other methods, difficulties occur from the slow process of scanning the entire volume of the object, layer by layer, by sintering or other fusion process. Furthermore, when sintering or heating a selected area, a relatively uniform temperature needs to be maintained on the powder surface in order to prevent deformations.